Ability Level up Bug [Gameplay]

Upon leveling up in the game a button above each ability will appear that allows you to click on it to level up. After leveling up an ability, those buttons are supposed to disappear, however all but one of those buttons disappears. You have no points left to level it up, but it still hovers there as if you can click it, but you can't. Upon next level up, leveling up that ability will return it to normal. However it is annoying to have it there when it's not supposed to be there. there happens on various champions and various spells, my last game it happened with graves's Q. This bug doesn't even occur every game, but every few games it does. Seems random as to when, which champ, what ability it happens with.